ptp: vmw: Convert to a platform driver

In all cases in which a struct acpi_driver is used for binding a driver
to an ACPI device object, a corresponding platform device is created by
the ACPI core and that device is regarded as a proper representation of
underlying hardware. Accordingly, a struct platform_driver should be
used by driver code to bind to that device. There are multiple reasons
why drivers should not bind directly to ACPI device objects [1].

Overall, it is better to bind drivers to platform devices than to their
ACPI companions, so convert the PTP VMware ACPI driver to a platform
one.

While this is not expected to alter functionality, it changes sysfs
layout and so it will be visible to user space.

Link: https://lore.kernel.org/all/[e-mail]/ [1]
Signed-off-by: Rafael J. Wysocki <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/ptp/ptp_vmw.c

···
 #include <linux/acpi.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/platform_device.h>
 #include <linux/ptp_clock_kernel.h>
 #include <asm/hypervisor.h>
 #include <asm/vmware.h>
···
  * ACPI driver ops for VMware "precision clock" virtual device.
  */
 
-static int ptp_vmw_acpi_add(struct acpi_device *device)
+static int ptp_vmw_acpi_probe(struct platform_device *pdev)
 {
 	ptp_vmw_clock = ptp_clock_register(&ptp_vmw_clock_info, NULL);
 	if (IS_ERR(ptp_vmw_clock)) {
···
 		return PTR_ERR(ptp_vmw_clock);
 	}
 
-	ptp_vmw_acpi_device = device;
+	ptp_vmw_acpi_device = ACPI_COMPANION(&pdev->dev);
 	return 0;
 }
 
-static void ptp_vmw_acpi_remove(struct acpi_device *device)
+static void ptp_vmw_acpi_remove(struct platform_device *pdev)
 {
 	ptp_clock_unregister(ptp_vmw_clock);
 }
···
 
 MODULE_DEVICE_TABLE(acpi, ptp_vmw_acpi_device_ids);
 
-static struct acpi_driver ptp_vmw_acpi_driver = {
-	.name = "ptp_vmw",
-	.ids = ptp_vmw_acpi_device_ids,
-	.ops = {
-		.add = ptp_vmw_acpi_add,
-		.remove	= ptp_vmw_acpi_remove
+static struct platform_driver ptp_vmw_acpi_driver = {
+	.probe = ptp_vmw_acpi_probe,
+	.remove = ptp_vmw_acpi_remove,
+	.driver = {
+		.name = "ptp_vmw_acpi",
+		.acpi_match_table = ptp_vmw_acpi_device_ids,
 	},
 };
 
···
 {
 	if (x86_hyper_type != X86_HYPER_VMWARE)
 		return -1;
-	return acpi_bus_register_driver(&ptp_vmw_acpi_driver);
+	return platform_driver_register(&ptp_vmw_acpi_driver);
 }
 
 static void __exit ptp_vmw_exit(void)
 {
-	acpi_bus_unregister_driver(&ptp_vmw_acpi_driver);
+	platform_driver_unregister(&ptp_vmw_acpi_driver);
 }
 
 module_init(ptp_vmw_init);